I've been noticing "Hissing Noise" coming from the rear passenger side (rear right hand side) of my 2011 Prius for a few days now. It sounds like the hissing noise is coming from the vent that's located on that side. Not sure what that does, but the hissing noise is usually present when I'm driving at 10MPH or up and it's gone when I'm less than 10MPH or at a complete stop. Any suggestion about what I should be looking at or how to diagnose this issue would be greatly appreciated. I have about 32K miles on the car.
sounds like the battery cooling fan. do you carry any pets? could a piece of paper or plastic have been sucked in?
take a look through the vent with a good light to see if anything is in there. i suppose the fan could be going south, but not likely.
It's probably just the HV battery fan doing what it's supposed to do. Depending on cabin temperature, the fan speed will vary to compensate. If it's extremely loud, then you might have an issue, otherwise - completely normal.
I've never heard mine, definitely check out the area, the fan may be working correctly but the air may be blocked at the other end.
